So you suggest he get the wanted adds or search online for a place he'd like to work and ask them to support his visa request?
I have a job now but took me a few months to secure when I got back. Most companies expect you to have all your visa stuff in order, even the local resturants flyer in the window type ads usually state you need the right to work in Australia.
Unless you know someone in the company, or the ad states otherwise the job application process is online only here. indeed.com.au seek.com.au
https://au.jora.com/ come to mind.
I think he'd have to come here with enough money to survive a month or two but there are definitely jobs here. If he's lived in USA I assumed he can speak at least some level of English? There is resturants in literally every suburb looking for staff, will be a non issue if he can get here on a visa with working rights.